What cause the engine to misfire when first start up after it been sit for a while?
1996 Chevrolet Tahoe 8 Cylinder the engine misfire when start up after it been sitting for a while i can drive it down the road and press on the gas real hard and the miss will go away until the engine sit for a while again and then it do the same thing i replace new spark plugs and wires distributor cap, when i replace the distributor cap it didn't miss for about 6 or 7 month and it start misfire again i replace the cap again what could be causing the misfiring? how do i fix this problem?
Cars & Trucks - Chevrolet - Tahoe - 1996 Chevrolet Tahoe
Answers & Comments
Could just be a loose spark plug wire. Depending on how long it's been sitting animals tend to hide under the hood may have knocked it loose. Drive it to orileys or autozone and they can scan your computer if you have a check engine light on which in my experience with a misfire it sets off the check engine light or your gas could be old also.
My guess is weak ignition coil. As a test, try gapping plugs 0.010" shorter. Dont change anything else, except plugs if fouled. If it runs without miss, just run shorter gap.
"how to test the ignition coil?
You can measure the coil primary and secondary resistance but likely the readings will be ok.
Reading high voltage in circuit requires special probe and a scope. So gapping plugs shorter is a diagnostic method that doesnt require special equipment.
If a shorter gap abates misfire, then replace coil. But small possibility it can still be other cause.
Leaking fuel injectors